Can coffee beans be brewed casually if they are of good quality? Why should we pay attention to water injection when making coffee by hand? What is the difference between large and small water currents?

In order to improve the communication with guests and friends, the hand-brewed coffee in most coffee shops is open-ended on-site production. As a result, the barista's concentration on water injection attracted a certain degree of incomprehension. Because there is such a saying in the industry: as long as the beans are good, then no matter how much coffee is made, the coffee is good. As a result, some friends will mistakenly think that as long as there is a good ingredient, and stable extraction parameters, then no matter how the water injection, can make a good hand to make coffee, water injection is not important.

But in fact, on the contrary! Water injection is also a very important "extraction parameter". Just like the cooking skills that chefs use when cooking, in order to heat, color, taste and thicken the dishes more evenly, they will stir-fry accurately and timely with different efforts at different time points. Bring this explanation into the water injection of hand flushing and it is easy to understand! In fact, hand-brewing coffee injection has only one purpose, that is: to evenly extract all coffee powder. Although this may sound like a very simple goal, we have to regulate the flow of water from different angles to ensure that all coffee powder is extracted evenly without causing it to extract unpleasant substances.

We all know that there are 30% soluble substances in a coffee bean, and not all of these 30% of the substances have to be extracted. Because there is nearly 1/4 of the material in it, which is unlikable and unacceptable. Of course, it's no good to extract too little. So we have to control the flow through various angles after the other parameters are fixed, so as to have a suitable extraction rate, and this is "water injection"! With regard to water injection, Qianjie believes that there are three main directions of regulation and control: "scope of water injection", "height of water injection", and "amount of water injected".

The range of water injection is like the big circle and small circle often mentioned in the front street, which is a change in the range of water injection, so that all coffee powder can be extracted evenly! If only fixed-point water injection, it is impossible to rely on capillarity alone to make all coffee powder get a suitable extraction rate. Because the injected water will have penetrating power, we need this penetrating force to cause the coffee powder to tumble, so that their aromatic substances can be better extracted by hot water. (central water injection)

If there are other ways of water injection, such as Z-shaped, cross, ∞ and so on, it will easily lead to uneven extraction because of the irregularity of water injection. Therefore, the water injection of hand-brewed coffee will mostly use a safe circle method, so that the coffee powder can be extracted evenly! "big circle" and "small circle" is a change in the range of water injection according to the state of the powder bed at different stages. It is worth mentioning that the faster the speed of the circle, the more times of stirring, and the higher the extraction efficiency. We need to determine the speed of the circle according to different cooking methods and different states of beans. (make a small circle)

The height of water injection determines the penetration of the water flow. When the water injection height is higher from the liquid level, the penetration is stronger, and the coffee powder is stirred more, which allows more substances to be extracted by hot water. Therefore, when the penetration force is higher, the extraction rate will increase, and vice versa.

However, too high water injection position can easily cause two problems, one is the loss of hot water temperature. When hot water is poured out from the mouth of the kettle, it will come into contact with a large amount of air, which will "take away" some of the heat from the hot water, resulting in a certain degree of cooling of the hot water, which means a reduction in extraction efficiency. so this is the first point we need to pay attention to (there are good and bad according to the situation)! The second problem is fine powder! In the process of grinding, the collision of coffee beans with other objects (coffee beans, knife head) will lead to the growth of fine powder. Fine powder also has different advantages and disadvantages, the advantage is that the right amount of it will make coffee more layered; the disadvantage is that because the particles are too fine, its existence is easy to clog the filter paper, especially under the stirring of large water flow, the fine powder that absorbs enough water will sink to the bottom with the stirring of large water flow, blocking the filter paper, which may lead to excessive extraction of the whole cup of coffee. Therefore, the size of the current should also be decided according to the situation!

The amount of water injected is often referred to as a large flow in front of the street, and a small flow refers to the amount of water injected in a period of time, or simply how much water is injected in a second. But there is no clear stipulation that how much water is injected in a second is a large flow and how much is a small flow, so generally speaking, the change in flow is based on the amount of water we currently inject!

For example, if the current amount of water injection in Qianjie is one second 5ml, then if you want to use a large flow, it will increase the injection volume to 6~7ml second, and if it is a small flow, it will reduce the injection volume to 3~4ml second! And the reason for the adjustment, because the size of the flow has different advantages! First of all, talk about the small flow, because the amount of water injected into the small flow is less, so it takes longer to complete the target water than the large flow, and this can make the hot water have more extraction space, so as to extract more coffee substances; the large flow, due to the injection of more water, is often higher than the launching speed of the filter cup, thus causing the rise of the powder bed and water level! The speed of launching is not only faster, but also it can make hot water extract all coffee powder more evenly. The disadvantage may be that the extraction time is too short and lead to insufficient extraction.

Therefore, very often, we do not use a certain method of water injection throughout the process, but use it together. Not only that, as mentioned earlier, the height of water injection and the range of circles all need to be observed to determine the type of use. And beans, no matter how good, can not stand chaos, reasonable extraction is still the best way to maximize the value of beans. Therefore, we can not underestimate the "water injection" this very important "extraction parameter"!

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